1. Field of the Invention
The present invention relates to a liquid injection recording head mounted on a liquid injection recording apparatus which performs a recording operation by the discharge of liquid droplets.
2. Description of the Related Art
A liquid injection recording apparatus is a so-called non-impact recording type recording apparatus, and is mounted with a liquid injection recording head which discharges liquid droplets.
FIGS. 9A and 9B are views for describing the structure of essential parts of a general liquid injection recording head. FIG. 9A is a plan view illustrating the structure of essential parts of a general liquid injection recording head 1000, and FIG. 9B is a sectional view taken along a section line 9B-9B illustrated in FIG. 9A.
In the liquid injection recording head 1000, as illustrated in FIG. 9B, a recording element substrate 1100 and an electric wiring board 1200 which are electrically connected to each other via a wire 1700 are attached to a supporting member 1400. In the electric wiring board 1200, as illustrated in FIG. 9B, a wiring member 1202 is formed on the front surface of a base film 1203. A coated region which has adhesive 1207 applied thereon and is covered with the cover film 1204, and an exposed region which is not covered with the cover film 1204 exist on the front surface of the wiring member 1202. The wire 1700 is connected to a portion of the exposed region. An electrical connection between the recording element substrate 1100 and the wire 1700 and an electrical connection between the electric wiring board 1200 and the wire 1700 are sealed using sealant 1300 and sealant 1301.
A liquid injection recording head aiming at preventing outflow of the sealant is suggested in the liquid injection recording head which has the above structure, and is disclosed in Japanese Patent Application Laid-Open No. H08-332729, and Japanese Patent No. 3592208, respectively. Japanese Patent Application Laid-Open No. H08-332729 discloses a liquid injection recording head which has the structure utilizing the thickness of the cover film as a wall which prevents the outflow of the sealant. Meanwhile, Japanese Patent No. 3592208 discloses a liquid injection recording head which uses low-viscosity sealant as sealant 1301 and uses high-viscosity sealant as sealant 1300. According to the liquid injection recording head disclosed in Japanese Patent No. 3592208, since the high-viscosity sealant is used for a sealed region where the spread of the sealant should be suppressed, the outflow of the sealant can be prevented.
In the liquid injection recording head 1000, adhesive 1207 is uniformly applied to the above-described coated region. However, a region where wiring 1202 is formed, and a region where no wiring is formed exist in the coated region. The region where the wiring 1202 is formed is thicker by the thickness of the wiring than the region where no wiring is formed. Therefore, in the manufacturing process of the cover film 1204, the adhesive 1207 applied to the region where the wiring 1202 is formed is extruded. As a result, the adhesive 1207 protrudes from an end 1500 in the region where the wiring 1202 is formed more than in the region in which no wiring is formed (refer to FIG. 9A). Specifically, a length L2 by which the adhesive 1207 protrudes from the end 1500 may be set to about 0.1 to 0.2 mm. Additionally, although a region L6 should be secured in the wiring member 1202 in order to connect the wire 1700 to the above-described exposed region, it is necessary to increase the plane area of the exposed region as the length L2 becomes long (refer to FIG. 9B). This will increase the region of an electric connection part, and as a result, will enlarge the liquid injection recording head.
In recent years, in the liquid injection recording head, the density of the wiring of the electric wiring board becomes high according to the miniaturization and increasing density of the recording element substrate. However, in the case of the liquid injection recording head 1000, when the density of the wiring become high, the percentage by which the sealed region is occupied by the wiring member 1202 will increase. Hence, due to the above-described reason, the electric wiring board 1200 tends to be enlarged according to the miniaturization and increasing density of the recording element substrate.